BENDIX SD-05-4630 manual Description, Operation, General, Brake Application

®

Bendix® Versajust™ Automatic Slack Adjuster

SD-05-4630

DESCRIPTION

The Bendix® Versajust™ automatic slack adjuster is designed for use on cam-actuated drum brakes, the type in use on most highway vehicles. Like a manual slack adjuster, the Versajust™ slack adjuster multiplies and transforms the linear force of the air actuator into a rotational force, or torque, which is used to apply the foundation brake. In addition, the Versajust slack adjuster automatically adjusts the clearance between the brake lining and drum to compensate for wear.

A variety of Bendix Versajust slack adjuster configurations are offered, including both straight arm and 5/8" yoke offset models. The Versajust slack adjuster is offered in arm lengths of 5, 51/2 and 6 inches, and worm gear splines to accommodate the standard 11/4" and 11/2" SAE 10C-,24-, and 28-tooth splines.

Either of two yoke designs (easy‑on and quick connect) in combination with an external manual adjuster hex provides for convenient installation and maintenance of the Bendix Versajust slack adjuster. Note: The manual adjuster hex is intended for use during installation. CAUTION: Automatic slack adjusters should not be adjusted manually to correct excessive push rod stroke.

OPERATION

GENERAL

The automatic adjustment provided by the Bendix Versajust slack adjuster results in consistent brake-lining-to-drum- clearance and brake actuator stroke. The key to its operation is the ability to complete the brake adjustment during the early part of each brake application and to cease adjusting as resistance to brake cam rotation begins to build. This aspect of the adjuster mechanism’s operation prevents over-adjustment caused by lining compression, actuator bracket deflection, drum and foundation brake component distortion, or brake component wear.

The Versajust slack adjuster incorporates a clutch‑type adjuster mechanism that continuously adjusts – in very small increments – as lining and drum wear occurs. The

adjustments made by the Versajust slack adjuster are, therefore, not in specific increments relative to actuator

stroke.

YOKE	YOKE
	PIN
	LINK
	PIN
	LINK
Compatible with	BOOT
Bendix® ASA-5®
Automatic Slack
Adjusters
MANUAL
ADJUSTMENT
HEX

WORM

GEAR

LUBE FITTING

FIGURE 1 - BENDIX® VERSAJUST™ AUTOMATIC SLACK

ADJUSTER

Note that the Versajust automatic slack adjuster is compatible with Bendix® ASA-5®automatic slack adjusters. Therefore, it is acceptable to have a Versajust automatic slack adjuster on one side of the axle and an ASA‑5 automatic slack adjuster on the other side of the same axle.

BRAKE APPLICATION

When the brakes are applied, the linear travel of the brake actuator’s push rod causes the Versajust slack adjuster to rotate the foundation brake camshaft, which in turn begins to force the brake shoes into contact with the drum. When the Versajust slack adjuster rotates, the yoke assembly pivots on the yoke pin, causing the link to be pulled upward.

The “teeth” on the link mesh with the adjuster mechanism pinion. As the link is pulled, it travels first through its free play and then causes the pinion to rotate. Rotation of the pinion is transmitted through the clutch spring to the worm

1